Survey meters are known as portable radiation measurement devices. Survey meters are devices for measuring, for example, environmental radiation and radiation from radioactive pollution sources. Patent Document 1 discloses a survey meter having a flat-plate shape as a whole. The survey meter has a tip portion, a middle portion, and a grip portion. The tip portion is connected to the middle portion via a bending portion. A display and an operating portion are provided on the upper surface of the middle portion. The grip portion has a thin flat form when seen from the horizontal direction and houses therein plate-shaped batteries as rechargeable secondary batteries.